Some people surrendering are being counselled about their apparently erroneous ways during Thailand's political crisis and released after a few hours.

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But most are taken away to undisclosed locations where they are given, according to sketchy reports, a green uniform, toothbrush and "time to think". They are cut off from the world, including their families.

After hours of conflicting reports, the junta confirmed late on Monday that deposed prime minister Yingluck Shinawatra had been released after spending three days being held at a military base outside Bangkok. She has not been seen in public since, and presumably Thailand's first woman prime minister is banned from talking to the media, which faces harsh censorship under the junta that seized power last Thursday.

Those detained include politicians and political activists from opposing groups, academics, writers, business people, police and military figures and journalists. About 250 Thais have been summoned so far while at least two members of the former ruling party have refused to give themselves up.

Key targets appear to be people aligned with former prime minister Thaksin Shinawatra, a tycoon living in exile whose Red Shirt support base is now in disarray despite earlier threats from its leaders to fight the coup.

Coup leader General Prayuth Chan-ocha said the detained political rivals were staying together "to love and be at peace" with each other.

But it didn't all go according to plan. Bitter political enemies refused in the first days of incarceration to sleep under the same roof, Thai media reported. Soldiers relented and put them in separate accommodation.

Deputy army spokesman Colonel Winthai Suwaree said no details about the detainees would be publicly released.

"This is a sensitive issue. We want everything to be in order, so we don't want information surrounding the detainees to be made public," he said.

Bolstered by endorsement from King Bhumibol Adulyadej, the world's longest serving monarch, General Prayuth, 60, who was due to retire as head of the army later this year, has emerged as a combative and sarcastic martial law leader who insists he will stay in power indefinitely.

The general appears to have embarked on a thorough purge of the deposed government and people aligned with Mr Thaksin, including Red Shirt leaders.

In the country's north authorities are tearing down signs depicting Red Shirt villages.

For ordinary Thais who have often endured coups and the suppression of popular movements, life goes on under martial law, with the most impact being from censorship of television, radio and newspapers and a 10pm to 5am curfew.

Among the latest warnings from the junta, which has been named the National Council for Peace and Order (NCPO), is that social media is being used "as a tool to provoke public hatred". Using social media to spread rumours has been the biggest problem for the coup-makers, the Bangkok Post quoted Colonel Winthai as saying.

The junta has also delivered repeated ominous warnings about growing anti-coup protests across Bangkok.

As protesters were gathered at Bangkok's Victory Monument an army officer speaking through a loud speaker on an army humvee accused the protesters of not loving Thailand. When they responded by throwing water bottles he called them scum.

The officer also turned his attention to the observing media.

"Foreign correspondents are scoundrels. They are here to sell Thailand," he said.

Despite the powerful military insisting for months it would not seize power to end Thailand's political crisis, the coup was carefully planned based on thorough intelligence and professionally executed across the entire nation.

General Prayuth, who said he had no option but to intervene to steer the country out of crisis and avoid further bloodshed, was one of the commanders of a 2006 coup to depose Mr Thaksin that was widely seen as a disastrous failure that damaged the military's reputation.

Instead of removing the challenge to Bangkok's elite establishment, the coup gave birth to a grass-roots anti-establishment movement composed of rural farmers and others who were fed up with decades of conservative rule by elites.

This time General Prayuth has implemented a wider crackdown while declining to publicly reveal his plans.

"If you want me to talk a lot, I won't have time to work," he told reporters. "Don't ask me a lot of questions."

General Prayuth said people “may wonder if we are competent or not ... I would say with determination I can do everything."